Nikolai_V Posted September 24, 2008 Share Posted September 24, 2008 Hey all - everyone here was very helpful with my last dumb question, regarding 3.9 manifolds on a 3.5 (oh and they do work damn well, it revs much better). My latest dilemma is this: the old girl is getting a bit tired (mileage over 200k kms), and is starting to get a bit of frothing through blow by when I look in the rocker covers (yellowish foam in the oil filler cap). It still revs out okay, but is just feeling a little weak, and fuel consumption is starting to gradualy get worse. I know its not the head gaskets as oil and antifreeze are uncontaminated, and levels not changing. The cam is well worn (through visual inspection), and i`m considering replacing it. The question though, is there any point just doing the cam? (the engine runs well by the way, starts well etc), or should I attend to <say> rings and bores, get a valve grind etc at the same time. Its about NZD$3-4k for a freshen-up of the engine, against about $400 for a cam. On the other hand, am I best just getting a 3.9 out of a discovery (I could buy a whole disco for about 2k) and throwing that in, with my carbs and LPG in place of the EFI? Finally, i`m pretty mechanically minded, have rebuilt pushrod motors (Subaru`s and VW`s) in the past, is it worth me doing the work myself, or should I pay someone for the priveledge. It might seem daft to spend money on a 78 2-door, but its rust free and all the trim is in good nick, so I think its worth keeping. Plus I think it drives much nicer than a discovery or my series three - and the 2-doors look better... Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted September 24, 2008 Share Posted September 24, 2008 The 2-door is worth keeping - good ones are getting rare. Rebuilding the 3.5 isn't a difficult job, they're fairly basic engines and the parts are cheap enough (at least over here). I wouldn't want to pay someone the money you quoted to do it - buying the 3.9 and dropping it in is the best bet, although keeping the EFi or going MegaSquirt would give far better performance than dumping carbs onto the poor old thing. Quote Link to comment Share on other sites More sharing options...
JimAttrill Posted September 24, 2008 Share Posted September 24, 2008 And as we found out on fitting a 3.5 carb motor to a Disco I efi chassis, the fuel pump is too powerful for the carbs which requires all sorts of mucking about trying to fit a Defender V8 pump into the framework (and fuel level float) of the efi pump. Before you ask why we are doing such a thing, the owner blew up the 3.9 motor sort of terminally and the only V8 we could get at a reasonable price was a carb motor. Quote Link to comment Share on other sites More sharing options...
Ally V8 Posted September 24, 2008 Share Posted September 24, 2008 I'd stick with the 3.5 and rebuild it,they are much better blocks than the bigger ones - unless you are willing to go all the way to top hat liners. Quote Link to comment Share on other sites More sharing options...
Green200tdi Posted September 24, 2008 Share Posted September 24, 2008 Hi, if your looking for a few tips on the 3.5 engine i got loads of pics on my webby, www.therangieweb.piczo.com just go to the 3.5 strip down and rebuild pages,it should give you some sort of idea, if not feel free to pm me. mark Quote Link to comment Share on other sites More sharing options...
Hybrid_From_Hell Posted September 24, 2008 Share Posted September 24, 2008 At that mieagle I'll bet cam lobe 7 will be worn badly, replacing the camshaft and lifters could restore the engine nicely BUT Before you do this there is an easy way to judge the internal condition of your engine Remove either of the rocker covers, then look at the head top surface looking up at you .... and the rocker cover bottom If it has what looks like black cornflakes.......... then you wasting your money on a Cam and Lifter kit, - the engine has had it If it is just black, but without the cornflakes, ....then its very well worn, .....and maybe worth rings / mains / big end deglaze etc. Dark brown - just go fot the cam, you may get away with it Light brown / possibly even seeing the ali underneath,........... engine is good, foir the cam and lifters HTH Nige Quote Link to comment Share on other sites More sharing options...
paintman Posted September 30, 2008 Share Posted September 30, 2008 You must replace the cam AND the followers as a set. One without the other will very quickly destroy the new item. Quote Link to comment Share on other sites More sharing options...
Green200tdi Posted September 30, 2008 Share Posted September 30, 2008 If it has what looks like black cornflakes.......... then you wasting your money on a Cam and Lifter kit, - the engine has had it Not sure i agree with this, as i had this in my v8,i think so long as your bores are ok then the rest is childs play to replace and at very little cost, could be just down to bad servicing, check my pics on my site will give you some sort of idea ,www.therangieweb.piczo.com go to v8 strip down,some real bad pics there, but she washed up a treat,and is now bottom end rebuilt,just waiting for cam lifters and timing gear to finish. Quote Link to comment Share on other sites More sharing options...
Bull Bar Cowboy Posted September 30, 2008 Share Posted September 30, 2008 If it has what looks like black cornflakes.......... then you wasting your money on a Cam and Lifter kit, - the engine has had it Not sure i agree with this, as i had this in my v8,i think so long as your bores are ok then the rest is childs play to replace and at very little cost, could be just down to bad servicing, check my pics on my site will give you some sort of idea ,www.therangieweb.piczo.com go to v8 strip down,some real bad pics there, but she washed up a treat,and is now bottom end rebuilt,just waiting for cam lifters and timing gear to finish. I have looked at your rebuild pics and unfortunately I see several flaws ……….. Yes, it has cleaned up well, but did you measure the bores for ovality ………… on an engine in the condition of yours I would have expected to see between 3 & 5 thou ovality and that sort of wear is re-bore territory. Also have you micro inspected the centre main bearing web for cracking ? In another pic you show the valves all loose in a box with the springs next to them ……….. the springs and valves should be numbered so that they go back into the same guide positions……… failure to do this will lead to heavy oil consumption as there is a fair chance the most worn valve will end up in the most worn guide. You say the rockers have cleaned up nice ………….. yes they may look good from the outside but I can guarantee that the shaft and rockers are both very badly worn and will not give the full valve lift. Did you have the crank reground ? …………….I seen no mention of measuring the crank and dry fitted shells to ensure the clearances are correct ………….. also I see no measurement of the crank endfloat…….. What you have done is very good, but if I have read it correctly, then you may be disappointed with the results ……….. if all of the above has been attended to then I apologise for the criticism………. just reading the pictures is not always easy. Also rebuilding with just oil is not good .................... use something like build lube or bearing guard as they are designed to stay put and then dissolve as the pressure builds.............. BTW, my rebuild is here….............. http://forums.lr4x4.com/index.php?showtopi...mp;hl=whats+BHP Quote Link to comment Share on other sites More sharing options...
Green200tdi Posted September 30, 2008 Share Posted September 30, 2008 No i like what you say, always open to what others have to say, i have reused the valves and put them back in any old order, reason for this is my bench calapsed,hence they all got muddled up, if like you say would happen then its not a big job to remove heads and start again, new vavls and guides ,as for end flote cracking and other mesuments are all fine,i do want to change the rockers but money is tight so see how we go,im of the oppinion that so long as the bottom end is ok then once the engin is in stuff like heads valves are a doddle to do in the car, Quote Link to comment Share on other sites More sharing options...
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